H3C Technologies H3C S5120 Series Switches - Manual (Page 669)

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z The MAC address aging timer takes effect globally on dynamic MAC address entries (learned or
administratively configured) only.
z In a stable network, when there has been no traffic activity for a long time, all the dynamic entries in
the MAC address table maintained by the device will be deleted. When it happens, the device
broadcasts a large amount of data packets, which may be listened to by unwanted users, resulting
in security hazards. In this case, you can configure mac-address timer no-aging for dynamic
MAC address entries, that is, not to age out dynamic MAC address entries, thus reducing
broadcasts and ensuring the stability and security of the network.
Configuring the MAC Learning Limit
Configuring the MAC learning limit on ports
As the MAC address table is growing, the forwarding performance of your device may degrade. To
prevent the MAC address table from getting so large that the forwarding performance is affected, you
can limit the number of MAC addresses that can be learned on a port.
Follow these steps to configure the MAC learning limit on an Ethernet port, Layer 2 aggregate interface,
or the Ethernet ports in a port group:
To do… Use the command… Remarks
Enter system view system-view —
Enter Ethernet
interface view interface interface-type
interface-number
Enter port group view
port-group manual
port-group-name
Enter
Ethernet
interface
view, port
group view,
or Layer 2
aggregate
interface
view
Enter Layer 2
aggregate interface
view interface
bridge-aggregation
interface-number
Use any of these three
commands.
The configuration you make in
Ethernet interface view or
Layer 2 aggregate interface
view takes effect on the current
interface only; the configuration
you make in port group view
takes effect on all the member
ports in the port group.
Configure the MAC learning limit on an
Ethernet port, Layer 2 aggregate
interface or port group, and configure
whether frames with unknown source
MAC addresses can be forwarded or
not when the MAC learning limit is
reached
mac-address
max-mac-count { count
| disable-forwarding }
Required
The default maximum number
of MAC addresses that can be
learned is not configured.
When the MAC learning limit is
reached, frames with unknown
source MAC addresses are
forwarded by default.